This invention relates to a method and apparatus for forming small, or thin cross-section foam profiles having a structural skin and a foamed core.
In my copending application Ser. No. 227,575, now U.S. Pat. No. 3,922,328, filed Feb. 18, 1972, I have described a method and apparatus for making structural foam profiles having large cross-section by drawing partially expanded resin material through a chilled shaping or sizing die. The material continues its expansion in the interior of the profile with resultant development of porosity in the core of the profile while the surface layer is cooled and hardens as a substantially unexpanded structural shell. A disadvantage of the method described in application Ser. No. 227,575 is that the shaping die is stationary and hence the interface between the die and the moving resin profile may be lubricated to prevent friction and/or scoring of the surface of the profile.